Respiratory signal detection and time domain signal processing method and system

Abstract

A respiratory signal detection and time domain signal processing method and system classifies respiratory phases and determines respiratory time data useful in respiratory health determinations. The method and system analyze respiratory signals collected at multiple detection points at least one of which ensures that respiratory phases can be properly classified. Moreover, the method and system employ a time domain signal processing approach that facilitates determination of respiratory time data while realizing savings in computing power relative to frequency domain processing approaches.

1 . A time domain signal processing method, comprising the steps of:
 determining starting points for a plurality of respiratory phases using a tracheal respiratory signal; and   classifying the respiratory phases into inspiratory and expiratory phases using the starting points and a chest respiratory signal.   
   
   
       2 . The method of  claim 1 , further comprising the step of determining respiratory time data using the starting points and the classified respiratory phases. 
   
   
       3 . The method of  claim 2 , wherein the respiratory time data comprise one or more of average inspiratory time or average fractional inspiratory time. 
   
   
       4 . The method of  claim 1 , further comprising the step of applying a band-pass filter to the tracheal respiratory signal. 
   
   
       5 . The method of  claim 1 , further comprising the step of applying a smooth finite impulse response (FIR) filter to the tracheal respiratory signal. 
   
   
       6 . The method of  claim 1 , further comprising the step of down-sampling the tracheal respiratory signal. 
   
   
       7 . The method of  claim 1 , further comprising the step of applying an autocorrelation function to the tracheal respiratory signal. 
   
   
       8 . The method of  claim 1 , further comprising the step of applying a band-pass filter to the chest respiratory signal. 
   
   
       9 . The method of  claim 1 , further comprising the step of applying a smooth FIR filter to the chest respiratory signal. 
   
   
       10 . The method of  claim 1 , further comprising the steps of collecting and amplifying the tracheal respiratory signal and the chest respiratory signal. 
   
   
       11 . A time domain signal processing method, comprising the steps of:
 determining starting points for a plurality of respiratory phases using a respiratory signal from a first body position;   classifying the respiratory phases into inspiratory and expiratory phases using the starting points and a respiratory signal from a second body position; and   determining respiratory time data using the starting points and the classified respiratory phases.   
   
   
       12 . The method of  claim 11 , wherein the first body position is the trachea and the second body position is the chest. 
   
   
       13 . The method of  claim 11 , wherein the first body position is the trachea and the second body position is the back. 
   
   
       14 . The method of  claim 11 , wherein the respiratory time data comprise one or more of average inspiratory time or average fractional inspiratory time. 
   
   
       15 . A respiratory signal detection and signal processing system, comprising:
 first and second respiratory sound transducers adapted to collect first and second collected respiratory signals from first and second body positions, respectively; and   a time domain signal processor adopted to receive first and second received respiratory signals based on the first and second collected respiratory signals, respectively, wherein the time domain signal processor determines starting points for a plurality of respiratory phases using the first received respiratory signal, classifies the respiratory phases into inspiratory and expiratory phases using the starting points and the second received respiratory signal and determines respiratory time data using the starting points and the classified respiratory phases.   
   
   
       16 . The system of  claim 15 , wherein the first collected respiratory signal comprises a tracheal respiratory signal and the second collected respiratory signal comprises a chest respiratory signal. 
   
   
       17 . The system of  claim 15 , wherein the respiratory time data comprise one or more of average inspiratory time or average fractional inspiratory time. 
   
   
       18 . The system of  claim 15 , wherein the time domain signal processor is collocated with at least one of the first or second sound transducer. 
   
   
       19 . The system of  claim 15 , wherein the time domain signal processor is located remotely from the first and second sound transducers.